{"id":"85716172-478d-54d8-b24c-0aa7216146ba","stable_key":"6612c190-1948-5bcf-bbe3-a7f6c50fa3cf:l-proline-collagen-carbon","predicate":"supplies_proline_in","statement":"Carbon-13 glutamine tracing in human mammary cancer-associated fibroblasts demonstrated incorporation of newly synthesized proline into COL1A1 peptides.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"20d60963-8b40-5928-bca3-1b31ee720979","mechanism_event_label":"Collagen-building cells can make their own proline from glutamine.","subject":{"id":"8637bb39-2c30-5168-baaf-3e613d831db0","slug":"glutamine","display_name":"L-Glutamine","entity_type_key":"small_molecule"},"object":{"id":"9628da5b-f682-5532-b777-e8658d082139","slug":"col1a1","display_name":"Human collagen type I alpha 1 / COL1A1","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"20d60963-8b40-5928-bca3-1b31ee720979","stable_key":"6612c190-1948-5bcf-bbe3-a7f6c50fa3cf:l-proline-collagen-carbon-event","event_type":"observed_relationship","label":"Collagen-building cells can make their own proline from glutamine.","description":"Carbon-13 glutamine tracing in human mammary cancer-associated fibroblasts demonstrated incorporation of newly synthesized proline into COL1A1 peptides.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"8637bb39-2c30-5168-baaf-3e613d831db0","slug":"glutamine","display_name":"L-Glutamine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"9628da5b-f682-5532-b777-e8658d082139","slug":"col1a1","display_name":"Human collagen type I alpha 1 / COL1A1","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"70ccd53c-83ad-5251-a4f5-6370973bc40a","slug":"l-proline","display_name":"L-Proline","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"7da684a4-2641-5bc6-93ae-8c6aa384e487","slug":"glutamate","display_name":"L-Glutamate","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"6a5e6627-f4fd-5a02-b74b-371b629b076b","slug":"pycr1","display_name":"Human pyrroline-5-carboxylate reductase 1 / PYCR1","entity_type_key":"protein"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"0cf232e8-346d-54d2-97ee-659df9edaddb","slug":"collagen-proline-residues","display_name":"Collagen-bound proline residues","entity_type_key":"protein_state"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human fibroblast cultures; 2 mM labeled glutamine for 72 hours in the collagen-peptide experiment.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Atom tracing does not show that dietary glutamine or proline is the limiting substrate in a person. Correction record: Author correction PMID 35927357 / DOI 10.1038/s42255-022-00632-7 corrects the author surname Riero-Domingo to Riera-Domingo. It does not report a change to the experimental results. https://www.nature.com/articles/s42255-022-00632-7","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Proline collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-proline","display_name":"L-Proline","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Collagen-building cells can make their own proline from glutamine.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Cancer-associated fibroblasts require proline synthesis by PYCR1 for the deposition of pro-tumorigenic extracellular matrix. · 2022 · https://pubmed.ncbi.nlm.nih.gov/35760868/ · DOI 10.1038/s42255-022-00582-0","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"24dbdc51-5f04-549b-8b08-7c79bb2d1bcc","evidence_kind":"source_excerpt","locator":"Lines 246-252","start_line":246,"end_line":252,"excerpt":"## l-proline-collagen-carbon\nCollagen-building cells can make their own proline from glutamine.\nCarbon-13 glutamine tracing in human mammary cancer-associated fibroblasts demonstrated incorporation of newly synthesized proline into COL1A1 peptides.\nModel: Human fibroblast cultures; 2 mM labeled glutamine for 72 hours in the collagen-peptide experiment.\nLimitations: Atom tracing does not show that dietary glutamine or proline is the limiting substrate in a person. Correction record: Author correction PMID 35927357 / DOI 10.1038/s42255-022-00632-7 corrects the author surname Riero-Domingo to Riera-Domingo. It does not report a change to the experimental results. https://www.nature.com/articles/s42255-022-00632-7\nEvidence access: Primary full text\nCancer-associated fibroblasts require proline synthesis by PYCR1 for the deposition of pro-tumorigenic extracellular matrix. · 2022 · https://pubmed.ncbi.nlm.nih.gov/35760868/ · DOI 10.1038/s42255-022-00582-0","model_system":"Human fibroblast cultures; 2 mM labeled glutamine for 72 hours in the collagen-peptide experiment.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"e5aa7fc5-ee52-5376-8169-416082a89fd1","stable_key":"import-6612c190-1948-5bcf-bbe3-a7f6c50fa3cf","title":"L-Proline: synthesis, collagen processing, redox metabolism and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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